Semiconductor switching devices (switches, keys), such as diodes, thyristors, bipolar transistors, field effect transistors (MOSFETs) and the like, are widely used in various electronic devices. Semiconductor switching devices are used, for example, in power conversion systems, communication devices, control and monitoring devices, amplification devices, and the like. The semiconductor switching devices and the switching elements may control electric current by an on/off operation. Further, the performance of electronic devices may depend on the performance of the semiconductor switching devices used therein. The characteristics required for the semiconductor switching devices include high power efficiency, small size, high operation speed, low loss, high reliability and the like. Particularly, since the operating speed of the semiconductor switching devices affects the power efficiency and the operating frequency, semiconductor switching devices having a high switching speed are required.